V8 F-Bodys vs. V-TEC Hondas
 

I raced a '97 VTEC Prelude in the rain one night. I spun my tires off the line :doh:, and it took me 'til 4th gear (350 5-speed) to catch him, but once I did, I was gone. I was surprised how well it did, and figure with some simple mods and a good driver they'd be pretty dangerous cars. Have any of you guys good any good stories about them? Has any been beaten by one of these things?

If you rain in the rain you should have your head examined! I punched it the rain once when my car was stock I did a 180 into oncoming trafic at about 40 MPH. I was lucky no one was in the other lane. These cars have 2 much torque and 2 wide tires to f*** around like that. I would reconsider doing this again even if you want to teach 1 of those ricers a lesson.

It was my brother in the other car, and I don't have posi, so I don't get wrapped until I hit a corner.

Well, most hondas perform best on the highway... and Vtec doesn't help with any power there. The daul profile cam is supposed to provide more low end power. So, thecar should do pretty well off the line and in the 0-60, but as you saw it didn't pose a threat at higher speeds. If you can beat a non-vtec honda on the highway then you can beat a vtec honda on the highway. The only time that this doesn't hold true is when you're dealing with the dual overhead cam models like the Si... but with a reasonably well tuned 350 they still should be very beatable.

I dunno about the older Vtec's. But my friend has a 2002 Civic, and I think I could beat him on my old Dyno Air :doh:

I am just glad I have both. An Z 28 and a VTEC 94 Accord. I am not a Honda expert but it seems like in my Honda you can tell approx. 4000 rpm that the power becomes more aggressive. It just doesn't seem like it a 4 cylinder motor.

Theres still nothing like that smooth V8 power though.

Chet

ChillPhatCat: I thought the cam that kicks in with VTEC gets power at high rpm? That's why it engages at high rpm.... ???

Yeah, I agree.

The VTEC does kick in at high RPM. But usually on the highway you try to keep the revs low. I think when he said high end, he meant high speed.

yes VTEC does kick in at high rpm's. on the rsx, it is at 5800. you can hear the engine tone start to scream and it almost feels like a kick and faster acceleration. it isn't for low rpm's like
chillphilcat said. no flaming intended

From what I read it is split... lots of people think it's for low end power and lots think it's for high end power... but look at it this way: The cam switches to a more agressive profile at higher RPM... So, in essence it gives you a more consistent power band... but is that a higher profile than the non-vtec engines? or is it less agressive to start with to give low RPM power, then switches to the normal profile?

I think the gap in our communication happened when I said it was for low end. I knew Vtec kicked in at high RPM, and that Vtec kicking in produces more high RPM power... But, vtec is just the name for the dual profile cam... not the power it produces at high RPM... I was talking more for high speed, but both profiles as I said, are tuned for a certain RPM range... one for low and one for high.

The bottom end is designed to be quiet and fuel efficient, but no tamer than a non-VTEC, and once it kicks in it switches to a more wild cam profile that would not be suitable at low RPMs.
By the way, this is what it stands for.

Variable valve
Timing and
Electronic lift
Control

I take them out at low end and top end:D And of course by this statement I mean the stock or slightly modded V-TECHs. People always say well if it was a turbo car or if it had this. Of course a car would beat my stock car if they are running a turbo or nos or a sc. Also, regarding the post, I would not race in the rain. That is just asking for trouble. If you had to brake it is hard enough as it is on dry land let alone rain slicked roads. Racing in rain=trouble. Anyways good kill.

I know all about the dangers of racing, but the place where I raced my bro is about 1/2 long, dead straight, and uphill with very good visibilty. But thanks for the concern (probably a little more my Camaro than for me,) but concern none the less.

Whats a car without a driver;) Just be careful. If you feel comfortable at the location of the race then go for it. The only problem with rain is it ruins the race. It is hard to launch a car in the rain. I prefer dry roads. That way I can use that torque without going sideways:p

I tied a Prelude from a stoplight up till about 60 (then I missed 3rd :doh: ah crap). Coulda' taken him (I think)

how does a cam "switch profiles"? this term doesnt make any sense. maybe the timing and fuel curves are altered, but i cant see how a cam has two different intake and exhaust patterns. the only way i see this happening is it has DOHC, but only uses one cam for low rpms and the second one activates in addition to the first at high rpms. someone please explain it to me

Try these babies out:

http://www.leecao.com/honda/vtec/dohcvtec.html
http://www.leecao.com/honda/vtec/sohcvtec.html
http://www.leecao.com/honda/vtec/sohcvtece.html
http://www.leecao.com/honda/vtec/3stagevtec.html

In the single overhead cam engine that is in my VTEC 94 Accord I believe it only work on the intake side. I would say its almost like adding the extra 2 barrels like on the 4 barrel carb when it does kick in.

I wish I could find the article that I read many years ago about how the VTEC was brought about by the Honda engineers.

It was invented literally in the lunch room. The engineers were eating with their chop sticks around the table when one looked at the other and saw the angle at which the chop sticks were together and thought would that work to raise or to keep open longer the valve for more fuel and therefore more power.

I hope I just said that correctly.

I can only image what the technology would do for a chevy V8.

Heres a pic of my 94 VTEC

Chet

The only explanation I've found says:

...at around 5000 rpm (in the Prelude) a mechanism within the engine shifts longitudinally (thanks to oil pressure), and a set of lobes tuned for higher performance take over controlling the valves. This can always be heard and occaisionally "felt" under hard acceleration as an extra shove in the back.

That still doesn't explain the Electronic lift Control though.

and also on a DOHC doesn't one cam control the xhaust while the other does the intake?

Yes.

My friend Rays 87 LX 5.0 that only has exhaust and cold air done to it beats SIs pretty easily, theres this one kid with a 2000 Prelude and he works for Honda so he has a lot done to it and Ray beat him by about 2 car lengths . Even though my other friend with a 90 LX 5.0 got beat by a all motor SI on the highway because he couldnt handle the turns and even on the straight the Civic was still pulling. But come to find out the civic has 300 horse.

an all motor SI pulling 300hp is BS

some of the big names for racers that are in the all motor class in the IDRC that pull 11's or so only have like 260 or so I think

Yeah, but on the highway with a VTEC equiped Honda, the engaging VTEC is only a heartbeat and downshift away, trust me, there are 5 Civics at my school, and I've been in 3 of them.

rx7speed: Yeah, 11's with 260HP, but have you seen the N/A Civic hatchbacks running 9's N/A???

N/A hatch running 9's?


mmm.... souinds interesting

the lowest I have heard them go was mid 10's with around 260 hp on a tube frame car

I can't see 9 in a civic hatch N/A... it would take a lot of work and the biggest engine they could fit in that car... might be possible, but would it be worth the $$ ?

I'd rather build a chevelle up w/ a supercharged 502 :D

I know it sounds crazy, but they was a magazine with a 9 second N/A hatchback on the cover. Didn't read the article, but I gaurantee it was running a 2.2L Prelude motor with some serious work. Probably bored out and stuff. There was also a recent magazine, don't remember which one, but it had a Sun creations or something Lotus Elise. It was a special tuner thing like Brabus Mercedes and Saleen Mustangs and stuff. They took the dinky lil Lotus 4 banger out of it and droped in a B18 integra engine in it, tuned to pump out something like 220-240hp(don't remember exactly how much), and the thing ran like 11's. For those of you that don't know, the Lotus Elise is a very VERY light car. They pit it against a Rustang Cobra R and it handed it it's @$$ on a silver platter :D

Nah Preludes look mean but they are very heavy for an import (over 2800 pounds). We have a few here that are turbocharged but I've heard they are slow. I've never raced one so I'm not really sure. I do know for sure that the prelude motor (the H22A) is an awesome motor for a civic hybrid setup ... I had a friend who had a civic hatchback (the older ones) a H22A swap (N/A) and a 5 speed and he was topping out 3rd gear @ 125 on the freeway (has been verified).

sounds fun and all but if its not RWD or AWD it gets no respect from me. :D

Hell, I beat a 98 Integra GSR 4 times a couple nights ago with my LG4. I had about 2-3 car lenghts on him from about 70-110. Zipperhead cars dont scare me. When one poses a threat, I go to the track and hop in my Dart. :D

You have to be real careful in the rain, especially all you V-8 guys with no traction (wish I had one:( ), rain, especially at the beginning of a storm when rain mixes with the oil and other crap on the road to make it real slippery. I've gone sideways making turns in my truck, and it has a V-6. Racing rocks, but losing it from having no traction blows. (Sorry to throw off the whole conversation of Preludes and VTEC races, guys)

I know all about racing in the rain. I'm quite used to it. I raced him in my hometown on Vancouver Island, and it rains there at least 3/4 of the time. The roads are always wet! Sucks for trying to keep my car clean.

Yeah, experience does help alot in slippery conditions. I don't mind the rain getting my car wet, a good coat of wax takes care of that, the worst is when it rains and then all the flowers bloom and get a yellow coat of pollen like an inch thick all over your car, it drives me nuts, especially since my truck is black. Anyone ever notice how when you start washing/waxing your car it is always clear out, but within 15 minutes theres black clouds billowing in??

Technology. On a DOHC VTEC motor there are two sets of cam profiles on the intake cam and two sets on the exhaust cam. On SOHC VTEC there are obviously different lobes for the intake as there are for the exhaust, but on the SOHC VTEC only the intake has extra lobes for VTEC.

How it works:
All the lobes on the cam are obviously spinning at the same time, opening/closing the valves. The VTEC lobes ARE hitting their own set of lifters (or whatever Honda uses) all the time, AND they are pushing farther than the "normal" lobes, BUT at this point they are NOT attached to the valve. So what happens is as the primary lobes come around, they push, push, push, and then lower back down, and all that corresponds to movement on the valve. At this same time, the VTEC lobes go push, push, push, push (more lift and duration I believe), then lower back down, HOWEVER since they are not locked onto the valve in any way, they just kinda float and don't do anything to the valve.

To engage these second set of lifters, there is a VTEC controller that doesn't send a signal as long as the engine is below XXXX RPM. When the engine is at or above XXXX RPM, it sends a signal to a solenoid, which allows oil pressure to push a pin.. This pin then locks all the secondary lifters onto the valve. Now, as they come around, the primary lobes push, push, push, then back down. All this pushes the valve, BUT before it goes back down, the VTEC lobe is still pushing, and since it's locked onto the valve, it keeps pushing and then goes back down, now making the valve go farther and stay open longer.

My car gets loose shifting into 2nd on wet streets because of the shift kit. I cant imaging hitting it off the line in the rain.

seriously tho i think it would be bad *** if chevy or any domestic took vtec or vvti or whatever and put it on a v8 or even v6- on a tpi setup you could have all that amazing low end torque and have high end power (or at least some high end power).Hehe but then wed be copying honda :(

I see lexus has copied the design from Honda and is using the technology on most of there motors now.

That would be something if GM would apply it to one of there V8's

Chet

Yeah, look what happened when we applied technology to V-8s already. ZR-1 anyone? DOHC + 32 valve + 350 CID=405 horsepower?? Imagine a iV-Tec 350?

Actually ford came up with variable valve timing first. Nowadays lots of car manufacturers use it ... Honda/Acura (Vtec), Toyota/Lexus (VVTi), BMW (VANOS), some new Ford 'sport compacts' (Ztec), and I'm sure more I'm not listing ...

CrazyHawaiian,

Ford?

What year did they invent it and motor did they use it in? I would have bet a ride in my Z28 that Honda did it first.

I have never heard about Ford having it. Interesting.

Chet

well toyota does use vtec (not just vvti,even tho they are basically the same)my friends celica ,which i think was a 2000 or 2001 had vtec.

yeah i heard that too. and the reason they didn't use it is because it wasn't worth the extra cost at the time. they only got like 10 - 15 extra hp outta it and that wasn't worth having an extra cam and stuff to them.
Andrew

what's with the new sunfire's and cavalier's?.. their ... eccotec? or whatyamacall it?.. a turbocarged quad4 in a FWD drag cavalier?.. or was it a N/A eccotec or whatyamacall it?

Variable lift is available for Chevy engines, from hotrocker.com. Basically their rocker arms allow the ratio to be changed on the fly. I think it's from about 1.1 -> 1.6 as the RPMs increase.

mousemaker, ever go to the Knox Mountain hillclimb?

Ecotec... they've got a few different versions. The tube-frame, alcohol-burning, single-turbo Cavalier is pushing about 750 horses, iirc. There's also a Sunfire, much closer to stock, with turbo, that does pretty damn well also, though I don't remember the numbers on that. Hot Rod and CHP have both done articles on this engine recently; look through those mags for more info.